Assange, who has spent the last seven months holed up in the Ecuadorian embassy in London after losing his battle against extradition, has let his rock-star status go to his head and believes he is above the law and exempt from criticism, she claimed.

Once akin to the on-the-run film hero played by Matt Damon he now risks becoming an Australian version of the founder of the Church of Scientology, the daughter of billionaire Sir James Goldsmith wrote in the New Statesman.

Khan, who is associate editor of the magazine, remembered when she first saw the infamous 2010 video of US troops killing down civilians in Iraq. She wrote: “I jokingly asked if Assange was the new Jason Bourne, on the run and persecuted by the state.

“It would be a tragedy if a man who has done so much good were to end up tolerating only disciples and unwavering devotion, more like an Australian L Ron Hubbard.”

Acknowledging that anyone carrying out work like Assange would be different, she added: “I have seen flashes of Assange’s charm, brilliance and insightfulness – but I have also seen how instantaneous rock-star status has the power to make even the most clear-headed idealist feel that they are above the law and exempt from criticism.”

The socialite attended court in December 2010 and, despite not knowing Assange, offered £20,000 to ensure his freedom.

When Assange jumped bail to seek asylum the security money paid by Khan and other celebrity backers, including John Pilger and Ken Loach, was forfeited to the court.

She now describes her “journey” with Assange as one from “admiration to demoralisation.”

The former wife of cricketer Imran Khan has executive produced Alex Gibney’s documentary about WikiLeaks – We Steal Secrets.

It was publicly denounced by Assange, who now has a cult like following, before he even saw it. He objected to the title despite her assurances it was based on a comment in the film by Michael Hayden, a former director of the CIA.

When she told him to see the film as a balanced portrayal he replied: “If it’s a fair film, it will be pro-Julian Assange.” Khan added: “Beware the celebrity who refers to himself in the third person.”

She decided to support Assange, editor-in-chief of WikiLeaks, as she believed by leaking diplomatic cables he had made many enemies, and she wanted to stand up for free speech, she claims.

But now she believes that his Wikileaks “has been guilty of the same obfuscation and misinformation as those it sought to expose, while its supporters are expected to follow, unquestioningly, in blinkered, cultish devotion.”

Former allies have fallen out with Assange over redactions, broken deals, money, ownership and control.

They include WikiLeaks collaborators, journalists, his former lawyer Mark Stephens and the publisher who paid him a reported £500,000 advance for a ghostwritten autobiography before Assange withdrew cooperation.

But despite the end of their love affair with Camp Assange, Khan vowed that if he were prosecuted in America “even his most disenchanted former supporters will take to the barricades in his defence.”

He has dodged attempts to respond to the opinion of legal experts who claim that he is no more vulnerable to extradition to the US in Sweden than in the UK, she added, a myth she feared she had perpetuated.

Khan maintained that there were still questions to be asked over Sweden’s handling of the investigation, but echoed calls she has made previously for Assange to answer the charges. She noted that while she does not regret putting up money she did to ensure his bail, not so he could hide from the allegations.

She wrote: “The women in question have human rights, too, and need resolution. Assange’s noble cause and his wish to avoid a US court does not trump their right to be heard in a Swedish court.”